Search-and-rescue operations are underway for two US Marine Corps aircraft involved in a “mishap” off the coast of Japan.

An F/A-18 fighter and a KC-130 cargo plane taking part in a aerial refueling exercise reportedly collided and crashed.

Two crew members have been found so far.

Search-and-rescue operations are underway for two US Marine Corps aircraft involved in a “mishap” off the coast of Japan, the Marine Corps said Wednesday.

The planes in question were an F/A-18 fighter and a KC-130 cargo plane that were taking part in aerial refueling exercise.

“The aircraft involved in the mishap had launched from Marine Corps Air Station Iwakuni and were conducting regularly scheduled training when the mishap occurred,” the service said in a statement published by USNI News.

The incident happened around 2 a.m. local time on December 6. Japanese search-and-rescue aircraft responded immediately, the Corps said, adding that the circumstances were under investigation.

The C-130 had five crew aboard and the F-18 two, according to the Marine Corps.

One of those missing was rescued alive, a spokeswomen for the 1st Marine Aircraft Wing said Wednesday evening. A second crew member was found around 60 miles from Shikoku island, according to the Associated Press, citing Japanese officials. The second crew member’s condition was unknown.

The search is ongoing in an area about 200 miles of the Japanese coast.